METHODS AND APPARATUS FOR SHARING COUNTER RESOURCES BETWEEN CoS/PRIORITY OR/AND BETWEEN EVC/VLAN TO SUPPORT FRAME LOSS MEASUREMENT

ABSTRACT

Embodiments including methods, apparatuses, and computer program products for calculating frame parameters for the purpose of measuring performance in a network based on the calculated frame parameters are disclosed. By automatically or manually provisioning at least two network elements in a star or other network topology to transmit and receive service frames (e.g., Loss Measurement Messages or Loss Measurement Responses), the embodiments enable network elements to share network resources, such as frame counters, thereby decreasing the number of frame counters needed to perform frame parameter measurements and increasing scalability for a given counter resource supported by a low cost network processor units.

BACKGROUND OF THE INVENTION

Operations, Administration, and Management (OAM) is a general term usedto describe activities, processes, tools, and standards that areinvolved with operating, administering, and managing a network. OAM maybe employed for performance monitoring, as defined in ITU-T Rec. Y.7131(05/2006) (hereinafter “Y.7131”), such as frame loss, frame loss ratio,frame delay, or frame delay variation, in order to assist with serviceand capacity planning.

Specifically, such OAM functions allow for the measurement of differentperformance parameters, which may be used for point-to-point Ethernetconnections. Performance parameters, such as frame loss ratio, framedelay, or frame delay variation, are applicable to service frames, whichconform to a level of bandwidth profile at an ingress Ethernet flowpoint of a point-to-point Ethernet connection to be delivered to anegress Ethernet flow point. As defined in Y.1731, frame loss ratio isdefined as a ratio, expressed as a percentage, of the number of serviceframes not delivered divided by the total number of service framesduring a time interval, where the number of service frames not deliveredis the difference between the number of service frames arriving at theingress Ethernet flow point and the number of service frames deliveredto the egress Ethernet flow point in the point-to-point Ethernetconnection. Also defined in Y.1731, frame loss measurement may be usedto collect counter values applicable for ingress and egress serviceframes where network resources, such as counters, maintain a count oftransmitted and received data frames between pairs of network elements.

Frame loss may be generally measured by transmitting frames withinformation from a network element to a peer network element, followedby receiving return frames with information of both the first networkelement and its peer network element from the peer network element inorder to calculate both a near-end frame loss measurement and far-endframe loss measurement, where near-end frame loss is associated withframe loss from the ingress data frames and far-end frame loss isassociated with frame loss from the egress data frames.

SUMMARY OF THE INVENTION

Embodiments of the present invention include methods, network elements,and computer program products to calculate frame parameters, such asframe loss and frame loss ratio in a Ethernet Virtual Connection (EVC)based on shared limited network element resources, such as counters, fora plurality of priorities of the EVC to improve scalability. In oneexample embodiment, a first network element (NE) transmits a messagewith information obtained from a shared resource of the first NE to aspecific second NE, for a priority and an EVC. The second NE transmits asecond message with information recorded from the first message and theinformation obtained from the shared resource of the second NE, to thefirst NE. Upon receiving a sufficient number of messages at the first NEfrom the second NE, the first NE calculates frame parameters, such asframe loss and frame loss ratio, for this priority and this EVC.Repeating these based on the same shared limited resource, it ispossible to calculate frame loss and frame loss ratio for each priorityand each EVC to measure the network performance.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1 is a network diagram including multiple network elementsconnected via a virtual local area network.

FIG. 2 is a network diagram illustrating a star topology that includes aplurality of network elements, where at least one network element isdesignated as a root node.

FIG. 3 is a block diagram illustrating a network element that includes acommunication module, calculation module, performance module, andcounter resource.

FIG. 4 is a flow diagram illustrating measuring an example embodiment ofperformance in a network according to the present invention.

FIG. 5 is a flow diagram illustrating an embodiment of a network elementprovisioned in a slave mode set in a non-ready state.

FIG. 6 is a flow diagram illustrating an embodiment of a network elementprovisioned in a master mode set in a transmitting state.

FIG. 7 is a diagrammatic model of an example of a frame format.

FIG. 8 is a diagrammatic view of an illustrative state diagram modelenabling transmission and receipt of Operations, Administrations, andMaintenance (OAM) frames.

DETAILED DESCRIPTION OF THE INVENTION

A description of example embodiments of the invention follows.

In order to measure frame loss and frame loss ratio, it is necessary tocount the number of frames transmitted and the number of frames receivedper Class of Service (CoS) or priority and per Ethernet VirtualConnection (EVC) or Virtual Local Area Network (VLAN). As used herein,“EVCs” may include or refer to, for example, a type of EVC such as aVirtual Local Area Network (VLAN), or other types of EVCs as may apply.Also as used herein, the term “priorities” may include, be based on, orrefer to, for example, class of service (CoS), or other type of priorityas may apply. The terms “EVC” and “VLAN” and the terms “priority” and“CoS” may be referred to herein separately as may be appropriate fordifferent example embodiments.

Priorities may be configured for an outbound packet, such as prioritiesas 0 through 7, which are then sent to a port, where the prioritydetermines which outbound queue the packet uses. For example, the singleended frame loss measurement method defined in Y.1731 PM needs 16N suchcounters for N EVCs with 8 priorities; in other words, the currentapproach in the art to measuring frame loss or frame loss ratio requiresan increased number of counters (16 times) for each EVC with 8priorities, such that for 8 EVCs with 8 priorities, 128 counters wouldbe required to measure frame loss and frame loss ratio.

Prior approaches to the frame loss measurement problem as described inY.1731, which discloses the standard for determining frame lossmeasurement, fails to remedy the scalability requirement since multiplecounters are needed per EVC (e.g., 16 counters). The standard describeseach Maintenance Entity Group End Point (MEP), such as an end point of amaintenance entity group that is capable of initiating and terminatingOAM frames for fault management and performance monitoring, on a networkmaintaining two local counters for each peer MEP and for each prioritybeing monitored in a point-to-point maintenance entity, assumingsufficient number of counters are supported. However, such a standardfails to meet customer expectations because most low cost NetworkProcessor Units (NPU) only support a limited number of counters, whichrestricts the ability to support frame loss measurement to the verylimited number of priorities and EVCs.

Therefore, prior approaches in the industry have failed to solve thisproblem due to the inadequacies of requiring a set of two counters perEVC per priority, assuming the NPU has sufficient resources to supportthose counters; therefore, any implementation per Y.1731 assumptions andspecifications is expensive, burdensome, and leads to customerdissatisfaction.

Disclosed example embodiments generally include methods, networkelements, and computer program products for sharing counter resourcesbetween priorities, specifying priority values, such that frame loss andframe loss ratio may be measured using fewer network resources, such ascounters, for the same, or more, EVCs. Example embodiments may serve toshare limited network element resources, such as counters, betweenpriorities and between EVCs within a network or plurality of networks.

Networks in which embodiments of the present invention may be employedinclude any known or future developed network topology, such as a startopology, tree topology, mesh topology or ring topology, where thenetwork includes at least two network elements.

Sharing frame counters between priorities can increase the number ofEVCs to have frame loss and frame loss ratio measured without increasingthe number of counters needed to perform the functions (e.g., 2 Ncounters for N EVCs are necessary, which is significantly less than therequired number of counters as in the current industry standard). Toincrease further the number of EVCs to have frame loss and frame lossratio measured for a given number of counters supported by the NPU,sharing counters between priorities and between EVCs is advantageousover the current standard. Advantages of example embodiments of thepresent invention include an increase in scalability for a given counterresource supported by a low cost NPU, which can, in turn, reduce thecosts.

Frame loss measurement and its corresponding frame loss ratiomeasurement are supported by a pair of network elements (NEs). One ofthe pair of NEs may behave like a master NE and can transmit (OAM frames(e.g., Loss Measurement Messages (LMMs)) to a peer NE with the countednumber of frames received and the counted number of frames transmittedencoded in the LMM. The other of the pair of NEs, the peer of themaster, may receive LMMs, may add its counted frames transmitted andcounted frames received encoded, and may transmit a Loss MeasurementReply (LMR) to the master NE, including at least some of the countedframe information. Finally, the master NE calculates frame loss andframe loss ratio based on the received LMR from the peer NE.

Example embodiments described herein define methods, apparatuses, andcomputer program products to share counter resources between prioritiesand between EVCs to collect samples of frame parameters, such as frameloss and/or frame loss ratio, within a given time interval.

FIG. 1 is a network diagram including an example network 100 in which anembodiment of the present invention may be employed. The network 100includes a Virtual Local Area Network (VLAN) 101, where the VLAN is atype of EVC, but, alternatively, can include other types of EVCs or anEVC (not shown), which may serve as an interface between two networkelements, NE 110 and NE 120, such as end points of network entities. Inthe example embodiment of FIG. 1, NE 110 is depicted in master mode andNE 120 is depicted in slave mode; however, any NE on a network may beconfigured or provisioned, either manually or automatically, as a masterNE or a slave NE. NE 110 and NE 120 may be connected by a suitable line,for example an Ethernet Virtual Private Line (EVPL) 103 used as a dataservice providing point-to-point Ethernet connection between a pair ofUser-Network Interfaces (UNIs) or an Ethernet Private Line (EPL) 104service, used as a data service via point-to-point EVC, which,generally, has an expectation of low frame loss ratio. Alternatively,network elements may be connected by a suitable connection line eithercurrently known in the art or other similar connections available in thefuture. While only NE 110 and NE 120 are depicted in FIG. 1, it shouldbe known by a person of ordinary skill in the art that additionalnetwork elements may be configured in a similar manner.

FIG. 1 further illustrates an example of transmitting at least two LMMframes 140 from the NE 110 and receiving at least two LMR frames 150 atNE 110 from the NE 120, as is disclosed in more detail below inreference to FIG. 2.

FIG. 2 is a network diagram illustrating a star topology 200 thatincludes a plurality of network elements 201(a)(i)-(xii), where at leastone network element is designated as a root node 202. In this exampleembodiment the root node is provisioned as the master NE, and all leafnodes in the network are provisioned as slave NEs. An example embodimentof the present invention, as illustrated in FIG. 2, includes a sharingof network element resources, such as a network resource or counters,among EVC and priorities in the network elements of a star topology.

In the example of FIG. 2, VLANs 296(a)-(k) are established or may beestablished among a group of NEs, i, ii, iii, . . . n, in the form of astar topology, and at least one NE that is a root of the star topology,either automatically provisioned as such, or manually assigned. In theexample star topology 200, the root NE 202 may be identified as a masterNE upon transmitting a first LMM 240 to a NE 201, which may beautomatically provisioned as a slave NE to its peer (master NE) uponreceiving the LMM 240, followed by transmitting a LMR 250 in response.

FIG. 2 further illustrates an example method to measure frame loss andframe loss ratio in a star topology. Frame loss measurement begins atone of the NEs, such as NE 202 designated as a root node, which, upontransmitting a first LMM 240, is provisioned as a master NE, in mastermode. The master NE transmits the first LMM 240, which includesinformation, such as a first VLAN Identifier(1) (VID) and lowestpriority bit=0 (p-bit) via VID(1) 296(a) to its peer NE, such as NE201(a)(vii). FIG. 2 further illustrates the peer NE 201(a)(vii)receiving the LMM 240, at which point the peer NE 201(a)(vii) isautomatically provisioned as the slave NE, to the master NE 202, inslave mode. The slave NE 201(a)(vii) compares the VID(1) and the p-bitof the received LMM information to the VID and priority of the slaveNE's counter. If the received LMM information matches the VID andpriority of the slave NE 201(a)(vii), then the slave NE sends an LMR 250back to the master NE in response to the received LMM 240 with countedinformation included. However, if the VID and p-bit information in theLMM do not match the slave NE's VID and priority, the slave NE201(a)(vii) updates its VID and the p-bit of its counter to match theVID and the p-bit to that of the received LMM and waiting for the nextLMM, but not sending an LMR.

In the example embodiment of FIG. 2, the master NE 202 continues totransmit a plurality of LMMs 240 until the master NE receives sufficientLMRs 250 from the slave NE 201(a)(vii) to calculate near-end frame loss,far-end frame loss, near-end frame loss ratio, and far-end frame lossratio, explained in more detail below. The calculated near-end frameloss, far-end frame loss, and near-end/far-end frame loss ratio are anexample set of samples and can be used to update histogram bins(described in detail below).

The master NE then updates the priority to the next priority and repeatsthis method until all priorities are completed and counted, or someother action occurs. Then the master NE updates the VID to the next VID,such as VID(2)-VID(11), i.e., 296(b)-(k), and repeats the process oftransmitting LMMs and receiving LMRs for each priority on each VLANuntil all priorities and all VLANs have been counted.

Example embodiments of the present invention may exist for any networktopology (not shown), such as a ring, mesh, hub topology, or othertopology now existing or used in the future. The other networktopologies may be partitioned into a group of sub-connections orsub-topologies that are similar to star topologies. Each suchsub-connection group or sub-topology may indentify one node as a rootNE, and, thereby form a root NE group. The NEs in the root group may beidentified by root node ID=1, 2, . . . m, where m is the number ofsub-connection groups. A protocol may be defined to coordinate betweenthose root-nodes within the root group to repeat steps defined for astar topology such that all root nodes within the root node groupcomplete their sample collection. Organization-specific information inthe form of type, length, and value in OAM can be used to exchange rootcoordination information for root node coordination protocol to assurethose root nodes are coordinated.

FIG. 3 is a block diagram illustrating a simplified network element (NE)300 that includes a communication module 360, a calculation module 370,a performance module 375, and a counter resource module 321. The NE 300shows a communication module 360 that receives information, such as datapackets or frames, from an input from an external source, such as anadditional NE, a head end node, an end-user, or other external source,that contains frame information, such as priority bits or VIDs. Thecommunication module 360 may check or update priority bit information,that may be stored temporarily or permanently in a storage bin, such asa queue, memory, or buffer, and VLAN or EVC information as needed fromtime to time or for an interval and further provide such, and other,information to a counter resource module 321 for counting or maintainingframe information. The example embodiment of NE 300 also shows acalculation module 370 for determining frame parameters, such as frameloss and frame loss ratio, which, in turn, is used by a performancemodule 375 for determining and/or measuring performance of a networkbased on calculated frame parameters. Any or all of such information maybe transmitted to or implemented by a memory or data storage for ahistogram bin (not shown) for use in displaying network performance to auser, such as an operator, or to other network elements. The NE 300 mayalso contain an input and output port, queue, or buffer, as is customaryin the art.

FIG. 4 is a flow diagram representing an example embodiment of thepresent invention, illustrating how frame loss and frame loss ratio maybe calculated and used to measure performance in a network. According tothe example embodiment, a method 400 of a frame loss measurement processincludes selecting a NE 401 as a master NE from among a plurality of NEsand enabling the NE 430 to transmit and receive counter resourcesinformation from a plurality of NEs. The method further includestransmitting 440 from the first NE counter resources information, suchas a LMM, to a second NE and receiving 450 second counter resourcesinformation, such as a LMR, from the second NE. Upon receiving at leasttwo sets of second counter information resources, the first NE uses thegathered counter resources information and calculates frame parameters470, which may be used to measure performance in the network 475. Themethod further includes checking a priority 480 in a memory, such as adatabase, buffer, or other similar structure, for additional priorities;if more priorities exist, the operation cycles again, updating thepriority 490, until all priorities have been checked and the frame lossmeasurement is performed for the corresponding priority and iscalculated. If no more priorities exist, the method further checks foradditional VLANs 485 that may exist; if more VLANs exist, the operationcycles again, updating the VLAN 495, until all VLANs have been checkedand counted.

As in the above embodiments, selecting a NE 401 may includeautomatically or manually selecting the NE and may optionally furtherinclude automatically or manually provisioning the first selected NE asa master NE. Similar to the selecting of a NE 401, enabling a NE 430 totransmit and receive counter resources information, or other informationthat may be necessary or beneficial for measuring performance in thenetwork, may include automatically or manually provisioning the NE inthe enabled state.

FIG. 5 is a flow diagram illustrating how a network element, provisionedin a slave state, may receive and transmit messages to aid in frame lossand frame loss ratio measurement. In an example embodiment of thepresent invention, after a second NE is provisioned, eitherautomatically or manually, and the first, master NE transmits a LMM, thesecond NE automatically becomes a slave NE to the master NE upon receiptof the LMM 540, which, if first initialized, transmission of LMMs mayinclude an initial priority-bit (p-bit) set as zero (0). The slave NEmay compare information, such as the p-bit of the received LMM, to thepriority of its counter 525. If the received information does not matchthe slave NE's information, the slave NE changes or resets or sets thepriority 520 of its counter to match the p-bit of the received LMM.Furthermore, if the received information does not match the slave NE'sinformation, the slave NE only changes or resets the priority of itscounter, as above; the slave NE does not continue to build and send aLMR at that state, but may await for an additional LMM to be receivedbefore continuing. However, if the information matches, the slave NEbuilds an OAM (e.g., LMR) based on the counted values and p-bit 535 andtransmits the LMR 550 to the master NE.

The method further includes the master NE repeating the messaging cycle503 by continuing to send LMMs until it receives sufficient LMRs fromits slave NE to calculate (not shown) near-end frame loss, near-endframe loss ratio, far-end frame loss, and far-end frame loss ratio, orother such frame parameters that may be useful for determining networkperformance, as one set of samples that may be used to update thehistogram bins. Continuing to refer to FIG. 5, prior to repeating at503, the master NE will increase the CoS (not shown) to the next CoS andtransmit a second LMM 540 with the new p-bit to be received by the slaveNE. The master NE will repeat the method 500 until the master NEreceives at least a second LMR 550 from the slave NE. Upon receiving atleast the second LMR from the slave NE, the master NE calculates (notshown) frame parameters from the provided information.

FIG. 6 is a flow diagram 600 illustrating how a counter resource of anetwork element, such as the network element of FIG. 3, may be shared tocalculate a frame loss or frame loss ratio sample based on LMMstransmitted from a first NE provisioned in master mode to a second NEprovisioned as a peer to the first NE and set in slave mode. An exampleembodiment of the present invention is disclosed as sharing counters,such as frame counters, between priorites for a plurality of EVCs. Foreach EVC, the counter resources, such as frame counters, are set tocount the number of frames beginning with the lowest priority-bit(p-bit), i.e., p-bit=0, or CoS, when frame loss and/or frame loss ratiomeasurement is enabled for both network elements in a pair of networkelements in a network. According to the example embodiment, a method 400of a network element in master mode includes beginning with a p-bitequal to zero 610 and resetting a first counter 620 at the master NE tocount frames with that p-bit. The example embodiment of the methodfurther includes building an LMM 630 based on the counted values and thep-bit and transmitting 640 the built LMM to the NE in slave mode. Themethod further includes determining 650 if the master NE has receivedtwo or more LMRs from the slave NE.

If two or more LMRs have not been received by the master NE, the methodfurther includes determining if a transmit interval has expired 645. Ifnot expired, the method again determines if the master NE has receivedtwo or more LMRs 650. However, if the transmit interval has expired,then the method returns to build 630 another LMM based on counted valuesand the p-bit, transmits the LMM 640 to the slave NE and further checksto determine if two or more LMRs have been received 650 at the masterNE. If two or more LMRs have been received, the master NE calculates aframe parameters sample 670. The method further determines if the p-bitequals seven (7) 680; if it does, the method 400 is complete for thatp-bit. If the p-bit is determined not to equal seven (7), then themethod increase the p-bit by one 690 and continues through steps 620 to680 until the p-bit equals seven (7) and is complete for that priority.

It is normally required to collect frame loss or frame loss ratiosamples in a given time interval to generate a histogram diagram. Thehistogram diagram (not shown) may be a group of bins B(i), with each bindefined as two boundary points B(i)=[S(i), S(i+1)]. If the sample (frameloss ratio or frame loss) has a number between [S(i), S(i+1)], B(i) willbe incremented by 1. It is expected to collect those frame loss or frameloss ratio samples for all EVCs and all priorities for a given timeinterval, e.g., a 5 minute interval, a 15 minute interval, 24 hourinterval, etc.).

FIG. 7 is a diagrammatic model of an example of a frame format 700. Theexample frame includes possible components carried in the frame 700.Frame 700 may include a DMAC 711 representing a destination Media AccessControl (MAC) address, which may be used to identify a recipient, suchas an end-user or next network element and a SMAC 712 representing asource MAC address, which may be used by a receiving device. The exampleembodiment of frame 700 further includes a S-TAG 713 representing aservice tag, a C-TAG 714 representing a customer tag, and an Ethertype715 representing which protocol is encapsulated in the payload of theEthernet frame. The example embodiment further includes at least one LMR735 or LMM 730, which may be exchanged by transmission and receipt, andcontain information that may be included and/or used in calculatingframe parameters. Frame 700's tail is a FCS 716 representing Frame CheckSequences, which allow for bits to be added to the end of a frame forerror detection purposes.

FIG. 8 is a diagrammatic view of an illustrative state diagram model 800enabling transmission and receipt of OAM frames for use in calculatingframe parameters and measuring performance in a network. In an exampleembodiment of the present invention, two network resources, such ascounters, may be included in the network elements that are enabled totransmit and receive frames. For example, a first counter in a first NE,Counter (TxFC) may be enabled per VLAN/EVC, per CoS/priority, and perport for counting transmitted data frames. Additionally, a secondcounter in a second NE, Counter (RxFC) may be enabled per VLAN/EVC, perCoS/priority, and per port for counting received data frames.

In some example embodiments, such as an embodiment that enables asingle-end Ethernet Loss Measurement function (ETH-LM), if a slave NE isenabled or set in a ready state 841, which may be overridden to anotReady state 842, and a LMM is received at the slave NE 850, then thestate of the slave NE enters or transitions to a notReady state 842,which can be overridden to the ready state 841, or back to ready stateafter reaching an LMM timeout state 845, as exemplified in the statetable below.

TABLE 1 REQUEST (Command and Event) STATE start stop overrideLMMrecieved LMMtimeOut ready transmit n/a notReady notReady n/a noReadyn/a n/a ready n/a ready Transmit n/a ready n/a n/a n/a n/a: no statechanges, stay in the same state or not happen in that state

If the slave NE is in a ready state 841, the master NE transmits an LMMPDU per VLAN/EVC per CoS/priority per port at a given period, whereTxFCf is a value of the local counter TxFC at the time of transmissionof the LMM frame (f). Next, the slave NE transmits the LMR PDU perVLAN/EVC per CoS/priority per port in response to the LMM received,where TxFCf is a value of TxFCf copied from the LMM frame, where RxFCfis a value of the local counter RxFCl at the time of LMM framereception, and where TxFCb is a value of the local counter TxFCl at thetime of transmission of the LMR frame. When the master NE receives asufficient number of LMRs, at least two, the master NE calculates aframe loss based on the at least two received LMRs at t_(p) and t_(c)(times), where far-end frame loss is calculated by the mathematicalequation: |TxFCb[t_(c)]−TxFCb[t_(p)]|−|RxFCb[t_(c)]−RxFCb[t_(p)]| andnear-end frame loss is calculated by the mathematical equation:|TxFCf[t_(c)]−TxFCf[t_(p)]|−RxFCl[t_(c)]−RxFCl[t_(p)]|.

In a first example embodiment of a state, Case 1, referring to FIG. 1,the master NE 110 may be connected to the slave NE 120 via a VLAN 101 oran EVC (not shown). In this example embodiment, the master NE and theslave NE are both set in priority sharing mode, with one of the NEs asthe master NE transmitting LMM only and another one of the NEs as theslave NE transmitting a LMR in response a to LMM only. The master andslave NEs may exist in one of three states, including: ready, notReady,or transmit and be responsive to one of three commands, including:start, stop, or override. The master and slave NEs may receive one oftwo events, including a LMM being received (LMMreceived) or an LMMtiming out (LMMtimeOut), where no LMM is received for a configurabletime (see Table 1).

In the example embodiment of Case 1, if the state action is set intransmit state, the master NE may set a p-bit, from lowest p-bit tohighest p-bit, setting counters per the p-bit, and transmitting an LMMwith values from counters and p-bit at a given period or interval untilsufficient LMRs (at least two) are received from the slave NE, inresponse to the LMMs, to calculate frame loss samples for the near-endand the far-end.

Further in the example embodiment of Case 1, if the state action is setin notReady state, the slave NE may compare the p-bit of the receivedLMM with p-bit of the slave NE's counter to determine if the p-bitsmatch. If matched, the slave NE may transmit a LMR with values from itscounter; however, if not matched, the slave NE may set its counter perthe p-bit of the received LMM but may not send a LMR until the slave NEreceives the next LMM from the master NE.

Furthermore, in the example embodiment of Case 1, if both NEs receive astart command at the same time, the master NE will enter transmit state,but the slave NE will deny the command. In this case, there is no locksituation.

In a second example embodiment, Case 2, a first NE 110 may be connectedto a second NE 120 via a VLAN 101. In this example embodiment, both thefirst NE and the second NE are set in priority sharing mode, with bothof the first NE 110 and the second NE 120 transmitting LMMs andtransmitting LMRs in response to the LMMs, such that no NE isprovisioned as a master NE and no NE is provisioned as a slave NE.

In the example embodiment of Case 2, if the state action is set intransmit state, one of the first NE and second NEs may set a p-bit, fromlowest p-bit to highest p-bit, setting a counter per the p-bit, andtransmitting a LMM with values from the counter and p-bit at a givenperiod or interval to the other of the first and second NE, untilsufficient LMRs (at least two), are received from the other of the firstand second NE in response to the LMMs, to calculate frame parameters,such as frame loss samples for the near-end and/or the far-end.

Further in the example embodiment of Case 2, if the state action is setin notReady state, the other of the first and second NEs may compare thep-bit of the received LMM with the p-bit of the other of the first andsecond NE's counters to determine if the p-bits of the first and secondNEs match. If matched, the other of the first and second NEs maytransmit a LMR with values from its counter; however, if not matched,the other of the first and second NEs may set its counter per the p-bitof the received LMM, but may not send a LMR until the other NE receivesthe next LMM from the first NE.

Furthermore in the example embodiment of Case 2, if both NEs receive astart command at the same time and both NEs will enter a transmit state,known as a locking situation, and no LMR is received at either NE, then,after a period of time or an interval, both NEs may raise a notificationthat signals that the operator needs to issue a stop command to one NEto reset that NE from a transmit state to a ready state.

In a third example embodiment, Case 3, a first NE is set in prioritysharing more and a second NE is not set in priority sharing mode, buthas counter resources for all priorities such that the first NEtransmits LMMs only and the second NE transmits LMRs in response to thereceived LMMs only.

In the example embodiment of Case 3, if the state action is set intransmit state, the first NE may transmit a p-bit, from lowest p-bit tohighest p-bit, setting counters per the p-bit transmitted, andtransmitting a LMM with values from counters and p-bit at a given periodor interval until sufficient LMRs (at least two) are received from thesecond NE in response to the LMMs, to calculate frame loss samples forthe near-end and/or the far-end.

Further in the example embodiment of Case 3, unlike Cases 2 or 3, thefirst NE may never be provisioned or enter a notReady state. However, inCase 3, if the second NE transmits a LMM, it enters a locking situationwhere the first NE, if in a transmit state, may not be transitioned to anotReady state, but where the first NE is set in a ready state, it maybe transitioned to a notReady state (as explained in more detail below).

In a fourth example embodiment, Case 4, the first NE is set in prioritysharing mode and the second NE is not set in priority sharing mode, suchthat the second NE transmits LMMs only and the first NE transmits LMRsonly.

In the example embodiment of Case 4, if the first NE is set in thenotReady state, the first NE may compare the p-bit of the received LMMwith the p-bit of the first NE's counter. If matched, the first NE maytransmit a LMR with values from the first NE's counter to the second NE.However, if not matched, the first NE may set its counter per the p-bitof the received LMM, without transmitting a LMR, and enter a p-bit cyclemode with the current p-bit set. Further in the example embodiment ofCase 4, if the state action is set in cycle mode, the first NE, startingwith the current p-bit value, may adjust its counter to match the p-bitof the LMM, if it did not match, and transmit a LMR with a configurablenumber. The first NE may then set the p-bit to the next p-bit, ifavailable, and repeat the cycle until all p-bit values are processed.

In a fifth example embodiment, Case 5, a first NE is set in prioritysharing mode and a second NE is not set in priority sharing mode, suchthat both the first NE and the second NE may transmit both LMMs andLMRs.

In the example embodiment of Case 5, if the first NE is set in anotReady state, the first NE may compare the p-bit of the received LMMwith the p-bit of the first NE's counter. If matched, the first NE maytransmit a LMR with values from the first NE's counter to the second NE,which may calculate frame parameters based on the received LMRs.However, if not matched, the first NE, in the notReady state, may setits counter per the p-bit of the received LMM without transmitting aLMR, and enter a p-bit cycle mode with the current p-bit set. Further inthe example embodiment of Case 5, if the state action is set in cyclemode, the first NE, starting with the current p-bit, may adjust itscounter to match the p-bit of the LMM, if it did not match, and transmita LMR with a configurable number to the second NE, which may calculateframe parameters, such as frame loss and/or frame loss rationmeasurements, based on the received LMRs. The first NE may then set thecurrent p-bit to the next p-bit, if available, and restart the cycle.

Further example embodiments of the present invention may include anon-transitory computer readable medium containing instruction that maybe executed by a processor, and, when executed, cause the processor tomonitor the information, such as components or status, of at least afirst and second network element. It should be understood that elementsof the block and flow diagrams described herein may be implemented insoftware, hardware, firmware, or other similar medium determined in thefuture. In addition, the elements of the block and flow diagramsdescribed herein may be combined or divided in any manner in software,hardware, or firmware. If implemented in software, the software may bewritten in any language that can support the example embodimentsdisclosed herein. The software may be stored in any form of computerreadable medium, such as random access memory (RAM), read only memory(ROM), compact disk read only memory (CD-ROM), and so forth. Inoperation, a general purpose or application specific processor loads andexecutes software in a manner well understood in the art. It should beunderstood further that the block and flow diagrams may include more orfewer elements, be arranged or oriented differently, or be representeddifferently. It should be understood that implementation may dictate theblock, flow, and/or network diagrams and the number of block and flowdiagrams illustrating the execution of embodiments of the invention.

Any element in a claim that does not explicitly state “means for”performing a specified function, or “step for” performing a specificfunction, is not to be interpreted as a “means” or “step” clause asspecified by 35 U.S.C. §112, para. 6. In particular, the use of “stepof” in the claims herein is not intended to invoke the provisions of 35U.S.C. §112, para. 6.

While this invention has been particularly shown and described withreferences to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

1. A method of measuring performance in a network, the methodcomprising: enabling a first network element to transmit and receiveinformation regarding counter resources to and from a second networkelement, the counter resources being shared among a plurality ofpriorities or Class of Service (CoS) of a virtual local area network(VLAN) or Ethernet Virtual Connection (EVC); for each priority, (i)transmitting, from the first network element to the second networkelement, first counter resources information determined at the firstnetwork element, and (ii) receiving at the first network element, secondcounter resources information determined at the second network element;calculating frame parameters for each priority at the first networkelement as a function of the first and second counter resourcesinformation; and measuring for each priority the performance in thenetwork based on the calculated frame parameters.
 2. The method of claim1 wherein transmitting the first counter resources information includestransmitting a lost measurement message (LMM), and wherein receiving thesecond counter resources information includes receiving a lostmeasurement response (LMR).
 3. The method of claim 2 wherein the firstnetwork element is a master and the second network element is a slave.4. The method of claim 1 wherein the first and second network elementsare arranged in a star network topology, and wherein the first networkelement is a root of the star network topology.
 5. The method of claim 1wherein the first and second network elements are part of a mesh networktopology, and further including segmenting the mesh network topologyinto a plurality of star topologies.
 6. The method of claim 1 whereinthe network includes a plurality of VLANs, and wherein the counterresources are shared among the plurality of VLANs.
 7. The method ofclaim 1 wherein the counter resources include a first and a secondcounter resource associated with the VLAN, the first counter resourcefurther associated with the first network element, and the secondcounter resource further associated with the second network element. 8.The method of claim 1 wherein calculating frame parameters includescalculating a frame loss ratio or frame loss measurement.
 9. The methodof claim 1 wherein both the first and second network elements areenabled in a priority sharing mode, wherein one of the network elementsis configured to transmit a LMM and the other network element isconfigured to transmit a LMR in response to the LMM.
 10. The method ofclaim 1 wherein transmitting first counter resources information andreceiving second counter resources information includes: (a) setting aVLAN identifier (VID) of a LMM to indicate the VLAN; (b) setting apriority-bit (p-bit) of the LMM to indicate a first priority; (c)transmitting the LMM to the second network element; (d) comparing theVID and p-bit of the LMM to a VID and p-bit of the second counterresource; (e) determining if the VID and p-bit of the LMM are equal tothe VID and p-bit of the second counter resource; (f) if equal,generating a LMR and transmitting the LMR to the first network element,and if not equal, changing the VID and p-bit of the second counterresource to equal the VID and p-bit of the LMM; (g) receiving the LMR atthe first network element; (h) repeating (c)-(g) until the first networkelement receives at least two LMRs from the second network element; (i)calculating, for the priority indicated by the p-bit, a near-end frameloss and a far-end frame loss; (j) updating the p-bit of the next LMM toindicate a next priority; (k) repeating (c)-(j) for each priority. 11.The method of claim 10 wherein calculating frame parameters furtherincludes repeating (a)-(k) for all VLANs in a case of multiple VLANssharing the resource.
 12. The method of claim 10 wherein calculating thenear-end frame loss measurement includes calculating the differencebetween (i) a number of frames transmitted from the first networkelement during a given time period, the given time period based ontransmission time of LMMs and (ii) a number of frames received from thesecond network element during the given time period.
 13. The method ofclaim 10 wherein calculating the far-end frame loss measurement includescalculating the difference between (i) a number of frames transmittedfrom the first network element during a given time period, the giventime period based on transmission time of LMRs and (ii) a number offrames received from the second network element during the given timeperiod.
 14. A network element for measuring performance in a network,the network element including: a first counter resource shared among aplurality of priorities of a Virtual Local Area Network (VLAN); acommunication module configured to (i) transmit, for each priority,information regarding the first counter resource and (ii) receive, fromanother network element, information regarding a second counter resourceshared among the plurality of priorities; a calculation moduleconfigured to calculate, for each priority, frame parameters as afunction of the first and second counter resources information; and aperformance module configured to measure, for each priority, performancein the network based on the calculated frame parameters.
 15. The networkelement of claim 14 wherein the first and second counter resources areshared among the plurality of priorities of a plurality of VLANs. 16.The network element of claim 14 wherein respective first and secondcounter resources are associated with a plurality of priorities of aplurality of VLANs, each first counter resource associated with thefirst network element and each second counter resource associated withthe second network element.
 17. The network element of claim 14 whereinthe network element is a root node of a star network topology.
 18. Thenetwork element of claim 14 wherein the network element is part of meshnetwork topology, the mesh network topology being separable into aplurality of star topologies.
 19. The network element of claim 14wherein the communication module is configured to transmit lostmeasurement messages (LMMs) and receive lost measurement responses(LMRs).
 20. The network element of claim 14 wherein the calculationmodule is configured to calculate a frame loss ratio or a frame lossmeasurement.
 21. A computer program product comprising a computerreadable medium having computer readable code stored thereon, which,when executed by a processor, causes the processor to: enable a firstnetwork element to transmit and receive information regarding counterresources to and from a second network element, at least one counterresource being shared among a plurality of priorities of a virtual localarea network (VLAN); for each priority, (i) transmit, from the firstnetwork element to the second network element, first counter resourcesinformation determined at the first network element, and (ii) receive,at the first network element, second counter resources informationdetermined at the second network element; calculate frame parameters foreach priority at the first network element as a function of the firstand second counter resources information; and measure, for eachpriority, the performance in the network based on the calculated frameparameters.